Title:
Mechanically flexible interconnects (MFIs) for large scale heterogeneous system integration
Mechanically flexible interconnects (MFIs) for large scale heterogeneous system integration
Author(s)
Zhang, Chaoqi
Advisor(s)
Bakir, Muhannad S.
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Abstract
In this research, wafer-level flexible input/output interconnection technologies,
Mechanically Flexible Interconnects (MFIs), have been developed. First, Au-NiW MFIs
with 65 µm vertical elastic range of motion are designed and fabricated. The gold
passivation layer is experimentally verified to not only lower the electrical resistance
but also significantly extend the life-time of the MFIs. In addition, a photoresist
spray-coating based fabrication process is developed to scale the in-line pitch of MFIs
from 150 µm to 50 µm. By adding a contact-tip, Au-NiW MFI could realize a rematable assembly on a substrate with uniform pads and a robust assembly on a
substrate with 45 µm surface variation. Last but not least, multi-pitch multi-height
MFIs (MPMH MFIs) are formed using double-lithography and double-reflow processes,
which can realize an MFI array containing MFIs with various heights and various
pitches. Using these advanced MFIs, large scale heterogeneous systems which can provide
high performance system-level interconnections are demonstrated. For example,
the demonstrated 3D interposer stacking enabled by MPMH MFIs is promising to
realize a low profile and cavity-free robust stacking system. Moreover, bridged multiinterposer
system is developed to address the reticle and yield limitations of realizing
a large scale system using current 2.5D integration technologies. The high-bandwidth
interconnection available within interposer can be extended by using a silicon chip
to bridge adjacent interposers. MFIs assisted thermal isolation is also developed to
alleviate thermal coupling in a high-performance 3D stacking system.
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Date Issued
2015-04-07
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Text
Resource Subtype
Dissertation